feat(monetization-261): prepare entitlement infrastructure and quota enforcement for release

- Add EntitlementSnapshot, EntitlementRevalidationUseCase, and BillingUseCases
- Add DriftEntitlementSnapshotRepository for offline entitlement caching
- Add HealthConnect gateway and integration
- Add quota enforcement in share acceptance (server and UI)
- Add entitlement API endpoints in server
- Add privacy policy v1 and release compliance checklist
- Add QA gates and device runbooks for release validation
- Add demo content screen and settings screen

Ticket #261

test/application/use_cases_test.dart

@@ -1216,10 +1216,19 @@ void main() {
           totalCaloriesKcal: 56,
         ),
       );
+    final activeWorkoutSensorUseCases =
+        ActiveWorkoutSensorUseCases(clock: clock)..recordTelemetrySample(
+          WatchSensorSample(
+            sessionId: session.metadata.id,
+            capturedAtEpochMs: clock.now().millisecondsSinceEpoch,
+            stepCount: 1320,
+          ),
+        );
     final useCase = CloseWorkoutSessionUseCase(
       sessionRepository: sessionRepository,
       historyRepository: historyRepository,
       telemetryRepository: telemetryRepository,
+      activeWorkoutSensorUseCases: activeWorkoutSensorUseCases,
       clock: clock,
       ids: _FakeIds(),
       originDeviceId: 'device-1',
@@ -1236,7 +1245,13 @@ void main() {
     expect(history.maxHeartRateBpm, 151);
     expect(history.totalDistanceMeters, 720);
     expect(history.totalCaloriesKcal, 56);
+    expect(history.totalSteps, 1320);
+    expect(
+      jsonDecode(history.historySnapshotJson),
+      containsPair('totalSteps', 1320),
+    );
     expect(historyRepository.histories.single, history);
+    await activeWorkoutSensorUseCases.dispose();
   });
 
   test('adjustRestSeconds persists adjusted rest duration', () async {
@@ -3240,6 +3255,7 @@ void main() {
           heartRateBpm: 120,
           distanceMeters: 500,
           caloriesKcal: 42,
+          stepCount: 900,
         ),
       );
       final duplicate = useCase.recordTelemetrySample(
@@ -3271,18 +3287,35 @@ void main() {
           ).millisecondsSinceEpoch,
           distanceMeters: 620,
           caloriesKcal: 48,
+          stepCount: 1320,
+        ),
+      );
+      final stepsOnly = useCase.recordTelemetrySample(
+        WatchTelemetrySample(
+          sampleId: 'sample-3',
+          sessionId: 'session-1',
+          capturedAtEpochMs: DateTime.utc(
+            2026,
+            7,
+            25,
+            12,
+            3,
+          ).millisecondsSinceEpoch,
+          stepCount: 1480,
         ),
       );
 
       expect(first?.latestHeartRateBpm, 120);
       expect(duplicate, isNull);
       expect(distanceOnly?.sampleCount, 2);
+      expect(stepsOnly?.sampleCount, 3);
       expect(distanceOnly?.latestHeartRateBpm, 120);
       expect(distanceOnly?.minHeartRateBpm, 120);
       expect(distanceOnly?.averageHeartRateBpm, 120);
       expect(distanceOnly?.maxHeartRateBpm, 120);
       expect(distanceOnly?.latestDistanceMeters, 620);
       expect(distanceOnly?.latestCaloriesKcal, 48);
+      expect(stepsOnly?.latestStepCount, 1480);
       await useCase.dispose();
     },
   );